Development of ductile cladding for TD-nickel turbine vane applications Final report, 5 Jul. 1967 - 31 Dec. 1968

Slurry technique for applying NI-CR-AL-SI coatings to TD-N

Distribution of survival times of deliberate Plasmodium falciparum infections in tertiary syphilis patients

Survival time data of Plasmodium falciparum infections from deliberate infection of human subjects with P. falciparum between 1940 and 1963 as a treatment for neurosyphilis in the USA (Georgia) have been used to test the fits of five commonly used parametric distributions for survival times using quantile-quantile plots. Our results suggest that the best fit is obtained from the Gompertz or Weibull distributions. This result has important implications for mathematical modelling of malaria, which has for the past century exclusively assumed that the duration of malaria infections has an exponential distribution. It is desirable to know the correct distribution because its shape profoundly influences the length of monitoring needed in an intervention programme for eliminating or reducing malari

Automated Calibration of Electrochemical Oxygen Sensors for Use in Compost Bedded Pack Barns

The objective of this study was to develop an automated calibration process for a galvanic cell type oxygen sensor. The manufacturer recommended a two-point calibration at room temperature; however, testing revealed that the response was not linear when both the temperature and oxygen concentrations varied. Thus, additional points were needed to generate a representative calibration equation and to reduce the sensor prediction interval. The calibration process needed to be capable of automatically recording sensor response (voltage) at an array of temperatures and oxygen concentrations. Calibration gases were used to precisely control the oxygen concentration inside a small manifold, and an electronically controlled water bath was used to regulate the sensor and gas temperature. A custom computer program controlled the sampling order and the data collection process. The responses for three sensors were recorded at six temperature (10°C, 20°C, 30°C, 40°C, 50°C, and 60°C) and five oxygen concentration (0%, 5%, 10%, 15%, and 20% O2 absolute) combinations, for a total of 30 measurements per calibration. Calibration data were used to create a second-degree polynomial model with oxygen sensor voltage and temperature as input parameters, which reduced the prediction interval by over 1% O2 for each of the three sensors tested. The resulting prediction intervals ranged between 0.75% and 0.95% O2. Three sensors were mounted in a prototype oxygen probe and tested under controlled conditions to demonstrate the ability to measure oxygen concentration versus depth in a composting environment

As-Applied Estimation of Volumetric Flow Rate from a Single Sprayer Nozzle Series Using Water-Sensitive Spray Cards

The objective of this study was to test the feasibility of using coverage measurements from water-sensitive spray cards to estimate the volumetric flow rate at an individual sprayer nozzle. TeeJet VisiFlow Even Flat Spray Tips were selected due to their uniform distribution of coverage. Spray distribution for each nozzle was validated using a spray patternator table with 2.5 cm sampling widths. A rotary test fixture translated water-sensitive spray cards through the spray dispersion (water at ambient conditions) at a constant angular velocity and a radius of 1.2 m. The test fixture measured volumetric flow and pressure at the nozzle and recorded data at a rate of 10 Hz. A helical gear pump and a piston-type pressure regulating valve were used to provide constant pressure. The first experiment fixed the test fixture speed at 3.14 rad s-1 and used varying pressures from 70 to 552 kPa (10 to 80 psi) in 70 kPa (10 psi) increments. First-order and second-order regression models were developed for the nozzle series, and validation data were collected at intermediate pressures to test the ability of the model to predict volumetric flow rates. The second experiment fixed the system pressure at 310 kPa (45 psi) and varied the speed of the test fixture at seven increments between 2.0 and 3.8 rad s-1. Spray cards were digitized using a scanner and processed for coverage using the MATLAB image processing toolbox. Results showed that the accuracy of the spray card method was within 1% full-scale of a commercial impeller flowmeter for a single series of nozzles moving at constant speed. Varying speed could be accounted for but required knowledge of the individual nozzle model. The method demonstrated in this study may be useful for field validation of variable-rate control systems on agricultural sprayers

Growth of wildtype and mutant E. coli strains in minimal media for optimal production of nucleic acids for preparing labeled nucleotides

Since RNAs lie at the center of most cellular processes, there is a need for synthesizing large amounts of RNAs made from stable isotope-labeled nucleotides to advance the study of their structure and dynamics by nuclear magnetic resonance (NMR) spectroscopy. A particularly effective means of obtaining labeled nucleotides is to harvest these nucleotides from bacteria grown in defined minimal media supplemented with 15NH4Cl and various carbon sources. Given the high cost of carbon precursors required for labeling nucleic acids for NMR studies, it becomes important to evaluate the optimal growth for commonly used strains under standard minimal media conditions. Such information is lacking. In this study, we characterize the growth for Escherichia coli strains K12, K10zwf, and DL323 in three minimal media with isotopic-labeled carbon sources of acetate, glycerol, and glycerol combined with formate. Of the three media, the LeMaster-Richards and the Studier media outperform the commonly used M9 media and both support optimal growth of E. coli for the production of nucleotides. However, the growth of all three E. coli strains in acetate is reduced almost twofold compared to growth in glycerol. Analysis of the metabolic pathway and previous gene array studies help to explain this differential growth in glycerol and acetate. These studies should benefit efforts to make selective 13C-15N isotopic-labeled nucleotides for synthesizing biologically important RNAs

Hydroxamic Acid-Based Histone Deacetylase (HDAC) Inhibitors Can Mediate Neuroprotection Independent of HDAC Inhibition

Histone deacetylase (HDAC) inhibition improves function and extends survival in rodent models of a host of neurological conditions, including stroke, and neurodegenerative diseases. Our understanding, however, of the contribution of individual HDAC isoforms to neuronal death is limited. In this study, we used selective chemical probes to assess the individual roles of the Class I HDAC isoforms in protecting Mus musculus primary cortical neurons from oxidative death. We demonstrated that the selective HDAC8 inhibitor PCI-34051 is a potent neuroprotective agent; and by taking advantage of both pharmacological and genetic tools, we established that HDAC8 is not critically involved in PCI-34051\u27s mechanism of action. We used BRD3811, an inactive ortholog of PCI-34051, and showed that, despite its inability to inhibit HDAC8, it exhibits robust neuroprotective properties. Furthermore, molecular deletion of HDAC8 proved insufficient to protect neurons from oxidative death, whereas both PCI-34051 and BRD3811 were able to protect neurons derived from HDAC8 knock-out mice. Finally, we designed and synthesized two new, orthogonal negative control compounds, BRD9715 and BRD8461, which lack the hydroxamic acid motif and showed that they stably penetrate cell membranes but are not neuroprotective. These results indicate that the protective effects of these hydroxamic acid-containing small molecules are likely unrelated to direct epigenetic regulation via HDAC inhibition, but rather due to their ability to bind metals. Our results suggest that hydroxamic acid-based HDAC inhibitors may mediate neuroprotection via HDAC-independent mechanisms and affirm the need for careful structure-activity relationship studies when using pharmacological approaches

The rise and fall of Anopheles arabiensis (Diptera: Culicidae) in a Tanzanian village

The continual recruitment of new individuals makes it difficult to study both the survival of multivoltine mosquitoes, and the size of the infectious reservoir in narural populations of malaria vectors. During long-term surveillance of a population of Anopheles gambiae Giles sensu lato in a Tanzanian village by daily light trapping, a temporary dry spell resulted in the cessation of recruitment for a period of 33 days, and a decline in numbers of A. arabiensis Patton caught from over 2000 to less than 10 in a sentinel house. Traps placed elsewhere in the village indicated similar proportionate declines although numbers caught varied according to location. A survival rate of 83% per day was estimated from the rate of population decline. Survival was unrelated to the size of the mosquitoes. The infectious reservoir (the chance of a mosquito acquiring an infection) was estimated to be 2% per feed. The exploitation of fortuitous events which temporarily eliminate a single stage in the life cycle has general applicability in the study of the bionomics of multivoltine insect

Effect of temperature anisotropy on the dynamics of geodesic acoustic modes

In this work, we revisit the linear gyro-kinetic theory of geodesic acoustic modes (GAMs) and derive a general dispersion relation for an arbitrary equilibrium distribution function of ions. A bi-Maxwellian distribution of ions is then used to study the effects of ion temperature anisotropy on GAM frequency and growth rate. We find that ion temperature anisotropy yields sensible modifications to both the GAM frequency and growth rate as both tend to increase with anisotropy and these results are strongly affected by the electron to ion temperature ratio

Energy Performance of Advanced Reboiled and Flash Stripper Configurations for CO2 Capture Using Monoethanolamine

CO2 capture by absorption using amine solvents has the potential to significantly reduce the CO2 emissions from fossil-fuel power plants. One of the major costs of this technology is the energy required for solvent regeneration. Complex process configurations claim to have promising potential to reduce the energy required for solvent regeneration. In this work, the effect of flow-sheet complexity is explored by studying two advanced stripping flow sheets: an advanced flash stripper and an advanced reboiled stripper. Both advanced configurations recover the stripping steam heat by means of a heat integration comprised of cold- and warm-rich solvent bypasses. The advanced configurations are simulated and optimized in Aspen Plus V.8.4 using 7 m monoethanolamine (MEA) with lean loading from 0.15 to 0.38 (mol CO2/mol MEA). The rich loading associated with each lean loading is determined by simulating the absorber providing 90% capture from flue gas with 4 mol % CO2, typical of a natural gas-fired turbine. The results are compared to a simple stripper in terms of total equivalent work. Both the advanced reboiled stripper and the advanced flash stripper require 12% less equivalent work than a simple stripper. The associated cold-rich and warm-rich bypasses for the optimum cases are, respectively, 20% and 50% for the advanced reboiled stripper and 15% and 35% for the advanced flash stripper

Endemicity response timelines for Plasmodium falciparum elimination

Background: The scaling up of malaria control and renewed calls for malaria eradication have raised interest in defining timelines for changes in malaria endemicity. Methods: The epidemiological theory for the decline in the Plasmodium falciparum parasite rate (PfPR, the prevalence of infection) following intervention was critically reviewed and where necessary extended to consider superinfection, heterogenous biting, and aging infections. Timelines for malaria control and elimination under different levels of intervention were then established using a wide range of candidate mathematical models. Analysis focused on the timelines from baseline to 1% and from 1% through the final stages of elimination. Results: The Ross-Macdonald model, which ignores superinfection, was used for planning during the Global Malaria Eradication Programme (GMEP). In models that consider superinfection, PfPR takes two to three years longer to reach 1% starting from a hyperendemic baseline, consistent with one of the few large-scale malaria control trials conducted in an African population with hyperendemic malaria. The time to elimination depends fundamentally upon the extent to which malaria transmission is interrupted and the size of the human population modelled. When the PfPR drops below 1%, almost all models predict similar and proportional declines in PfPR in consecutive years from 1% through to elimination and that the waiting time to reduce PfPR from 10% to 1% and from 1% to 0.1% are approximately equal, but the decay rate can increase over time if infections senesce. Conclusion: The theory described herein provides simple "rules of thumb" and likely time horizons for the impact of interventions for control and elimination. Starting from a hyperendemic baseline, the GMEP planning timelines, which were based on the Ross-Macdonald model with completely interrupted transmission, were inappropriate for setting endemicity timelines and they represent the most optimistic scenario for places with lower endemicity. Basic timelines from PfPR of 1% through elimination depend on population size and low-level transmission. These models provide a theoretical basis that can be further tailored to specific control and elimination scenarios